I bought a Hornet a few years ago with the full intention of reaming it out to k-hornet specs. The factory Hornet is notorious for having extremely generous chambers, contributing to poor accuracy so cutting a new chamber is a good idea, and while you're at it, going with the 'k' seems a no-brainer. I discovered, though, that my factory Hornet was a 1/2" shooter, so I left it unadulterated and it's since become my favourite rifle.
Anyway, the whole concept of the k-hornet is that you can fire Hornet brass in it to form k-brass. How else would you make k-hornet brass, anyway?